1. Field of the Invention
The present invention relates to an image signal processing unit and more particularly to amplification of the signal level of an effective pixel region.
2. Description of Related Art
Japanese Published Unexamined Patent Application No. 2001-28716 discloses a technique including a pixel signal gain amplification (P×GA) circuit. When amplifying pixel signals output from a CCD, pixel signals having variations in amplitude are input to a correlated double sampling (CDS) circuit and then transferred from the CDS circuit to the P×GA circuit. In the P×GA circuit, the pixel signals are individually amplified according to colors with a variably-settable gain to uniform the levels of the pixel signals. These signals are further amplified by a variable gain amplifier, so that amplified pixel signals including amplified noise are obtained.